Gross is the Bundesliga bottom club’s fourth manager already this season. Schalke have already dispensed with the services of David Wagner and Manuel Baum, while Huub Stevens recently lasted two games on an interim basis.
Schalke 04 have just four points from their 13 Bundesliga games this season and are without a win in their last 29 top flight matches.
"We have to be goal-oriented and work towards results. I want to feel the players' enthusiasm at all times," said former Tottenham, Basel and Stuttgart coach Gross.
"We need to have a good atmosphere in and around the team to be successful again. I will give everything so that we can accomplish our goals together."
Schalke's head of sport and communication Jochen Schneider added: "For Schalke 04, the next five months will be all about managing to stay in the Bundesliga. Christian Gross has shown in both Germany and England that he can successfully take on challenges like this.
"Christian Gross will give the team clear instructions and will set us on the right path with his unwavering expectations. We are sure of that."
Gross’ first game in charge of Schalke 04 will be against Hertha Berlin on January 2.
